Over the past couple of years, the technology has been used by several sushi restaurants in the UK and America. In 2012, Moshi Moshi, founded by Caroline Bennett, was the first to trial QR sushi, partnering with the Marine Stewardship Council (MSC), a seafood watch organisation. To celebrate its 10,000th MSC-certified dish, Moshi Moshi took up the challenge of telling its certified sustainable seafood story in a digital format.

"The beauty of working with MSC on QR sushi codes was that we had a credible partner reinforcing the message. Had it been a homemade video or webpage that we had [created ourselves], it would have had less impact" says Bennett.

The code was printed on rice paper and nori (edible seaweed), using squid ink. This was then placed on top of the fish. When a customer scanned it with a smartphone, they were directed to a website explaining where the fish was sourced. The technology is undoubtedly impressive, but the long-term impact on sustainability and consumer behaviour is questionable, as is whether other restaurants can adopt the technology successfully.

Stickers can be displayed on food packaging, highlighting that the meat within is 100% British, but this doesn't guarantee that it has been ethically sourced or that the supply chain is sustainable. "I am a truly cynical consumer; just because supermarkets put photos of their farmers on meat packages, doesn't reassure me of the husbandry of the animal one jot," says Bennett.

If fast food outlets and other multinational restaurants were to adopt the edible QR code idea, they could leave themselves open to unwelcome scrutiny. "A QR story needs to be linked to an independent judge of the value of its sustainability, otherwise [these] restaurants may be guilty of misleading consumers," continues Bennett. "If the stories behind the codes were known to be real rather than spin, perhaps more people will be encouraged to learn more about their food in this way."

It's simpler with sushi. The supply chain of a burger is near to invisible to the public eye, but the supply chain of a fish can be more traceable, particularly if you visit a dockyard or market.

The edible QR codes have since been adopted by numerous other establishments, including California's Harney Sushi.

After introducing the code, head chef Rob Ruiz found that they were taking record bookings and that there were increased sales of sashimi and straight fish. He said that it was because the diners now had more confidence in what was on their plate. He told National Geographic that he was "making sushi one plate at a time for every customer I can, and I'm making these QR codes so they won't forget about it".

However, there is one major fly in the ointment with edible QR codes. Bennett found that a majority of the customers in the Moshi Moshi trial didn't actually scan the code – simply because they didn't have a QR app on their smartphone.

This doesn't surprise Fabio Ceschel, a graphic designer who has previously developed an edible QR code as part of a client's rebranding. He believes that such gimmicks may wear off eventually. "People like information in a digital format because it's quick and easy to consume. It's on the go," he says. "People also like rewards. If they scan a code and there's no incentive, then it reduces the chances of one in the future."

If the codes are to revolutionise transparency in supply chains, there needs to be a further call to action once the customer has scanned it. If they leave the restaurant and haven't been prompted to go out and question the sustainability and source of the next food they buy, then it hasn't had the desired impact.

Ceschel doesn't expect edible QR codes to catch on with restaurants. The processes behind developing them can be intricate, he explains. "I've used squid ink and rice paper myself. On a scale of mass production, I'm not sure how feasible the operation would be if the aim is to be sustainable and keep costs as low as possible. [A local restaurant owner] could buy their own printer and edible ink, but that in itself would probably set them back at least somewhere in the region of £250-£500" he says. "Major restaurants wanting to develop a similar technique may end up cutting corners for quicker results."

Edible QR codes have made a splash in the seafood restaurant industry, but whether they can have real impact further afield is yet to be determined. As Bennett says, "reinforcing your own [sustainability] message, while not a bad thing if done with the right intention, runs the risk of adding to the ubiquitous 'green wash'."

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